April 2002

300,000 active subscribers in the North-West of Russia

Moscow, April 25, 2002. — Mobile TeleSystems OJSC (NYSE:MBT), Russia’s leading mobile cellular operator, and Telekom-XXI OJSC, MTS subsidiary in the North-West announced that a 300-thousandth subscriber has joined the MTS network in Saint Petersburg.

150 thousand MTS subscribers in Novosibirsk

Novosibirsk, Russian Federation — April 17, 2002 — OJSC “Mobile TeleSystems” (NYSE:MBT), Russia’s leading GSM 900/1800 mobile operator, and CJSC “Siberian Cellular Systems — 900”, MTS’s subsidiary in the Siberian federal region, announce today signing up the 150 thousandth active subscriber to the MTS network in Novosibirsk.

Mobile TeleSystems has acquired a controlling stake in the largest mobile operator of southern Russia: CJSC Kuban GSM

Moscow — Krasnodar, April 10, 2002. Mobile TeleSystems (NYSE:MBT), the largest Russian mobile operator and CJSC “Kuban GSM” have announced that Mobile TeleSystems completed the purchase of 51% of the outstanding shares of CJSC “Kuban GSM”. The shares were purchased in a series of transactions totalling $71.4 million.

Mobile TeleSystems announces financial results for the fourth quarter 2001 and year ended 31st December 2001

Moscow, Russian Federation — 10th April 2002 — Mobile TeleSystems OJSC (NYSE:MBT), Russia’s largest mobile cellular operator, today reports its results for the fourth quarter 2001 and the year ended 31st December 2001.

OJSC Mobile TeleSystems launches intranet roaming in the south of Russia

Moscow, April, 10, 2002. “Mobile TeleSystems” (NYSE:MBT), the largest Russian mobile operator, announces the launch of intranet roaming in the south of Russia through the networks of operators “DonTelekom” (the Rostov region) and “Kuban GSM” (the Krasnodar region, the republic of Adygeja).

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+ 7 495 223 20 25 ir@mts.ru

MTS Investor Relations
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